Straight-line frequency condenser



Feb. 25, 1930. c HORTON 1,748,481

STRAIGHT LINE FREQUENCY CONDENSER Filed July 14, 1925 2 Shets-Sheet l 11v VENTOR Char/es HorIOH BY wiiiii Feb. 25, 1930. c HORTON 1,748,481

STRAIGHT LINE FREQUENCY CONDENSER Filed July 14, 1925 2 Sheets-Sheet 2 INVENTOR I Char/as b qrzan BY 6 a 1 W 'ATTORNEY Patented Feb. 25, 1930 UNITED STATES PATENT OFFICE CHARLES HORTON, OF RIDGEFIELD PARK, NEW JERSEY, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO PILOT RADIO & TUBE CORPORATION, OF BROOKLYN, NEW YORK.

A CORPORATION OF DELAWARE STRAIGHT-LINE FREQUENCY CONDENSER Application filed Ju1y14, 1925.

densers adapted for application as tuning means in a radio communication.

At the present day, variable condensers have the property of varying capacity di-' rectly according to the displacement and the degree of'movement of the condenser plates with respect to the fixed condenser plates, whether the movement of the condenser plates be sliding or rotating, depending upon the type of condenser. These types of condensers produce a straight line function as regards the capacity plate displacement curve and' the parabolic function as regards the wave length plate displacement curve.

Some variable condensers have been formed with cut out rotor plates with the result that the wave length scale is spread so that the capacity varies as to the square of the deflection and the wave length is uniform along the entire length. However this form produces bunching of stations along portions of the dial, and practically prevents the reception of stations having low wavelengths, along the lower portion of the dial.

Up to date, there has been a tendency in radio reception tuning condensers to produce a straight line frequency device which as at present indicated, consistsof .a cut out rotor placed off center from the stator, which form of condenser will give a parabolic curve for the capacity plates displacement calibration curve, which curve lies parallel to the abscissa axis with a sudden change of slope of the curve merging at its upper end to a slope parallel to the ordinate axis. This form of condenser produces a straight line frequency plate displacement curve but in general has the inherent diificulty of being cumbersome and unwieldly in operation and rather large in size. The shape of the plates in such condenser are usually in the form of long narrow propeller-like sections which are placed considerably off center and as a result thereof produce a bulky instrument.

It is the purpose of this invention to provide a condenser wherein the statorplate is cut out, together with the rotor plate, both of which are centered with respect to one an- Serial No. 43,623.

.other and have formed'thereon reciprocal cut out portions so that the plates are symmetrical and in inverse arrangement.

In this manner a curve is produced which is a straight line frequency dial displacement calibration curve; and a gradually sloping capacity displacement curve having a configuration substantially parallel to the abscissa for a period equivalent to 40 as registered on the plate displacement dial, and at the same time having a sudden incline between 40 to 90 in the capacity curve with respect to the plate displacement and then a slope in the capacity curve substantially parallel to the ordinate axis from 90 to 100.

This form of condenser will function as a straight line capacity condenser having a maximum of three percent and operating independently up to 40 on the 100 scale; subsequently, the condenser will operate as 21- straight line frequency condenser acting from 40 to 90 on the 100 scale; and at the same time having a maximum of 47% and lastly, will operate as a straight line capacity condenser acting from 90 to 100 with a 50% maximum.

In this manner the particular form of condenser has been produced which ,will have a straight line frequency plate displacement curve and yet at the same timeproduce-a variable capacity platedisplacement curve wherein the beneficial effects of the straight line capacity and straight linefrequency functions of the condenser are introduced. In other words, by the use ofthese particular cut out stator and rotor elements wherein from 400 to 600 meters, will be bunched more or less regularly at the upper end of the dial. that is say from 50 to 100, whereas room will be left for the reception of new low wave length stations which are bound to come in the future, at the lower end of the dial. A

. which,

to provide a form of condenser wherein the' minimum of metal is used for the rotor and stator elements; to provide a plurality of cooperating portions in the respective-stator and rotor elements which will co-act to form different types of curves at respective dilferent displacement positions of the dial controlling the movement of the rotor plates; and to provide a simple and yet more effective form of condenser of the straight line frequency type.

Specifically, it is aimed to provide a condenser in which the rotor and stator plate elements have cut out )ortions whereby considerable metal hereto ore not producing any active function, is eliminated. Further it is aimed to provide a plurality of co-acting elements, one movable and one stationary, cut out so as to have curved surfaces symmetrical but inversel positioned from one another.

Still further it is aimed to provide a condenser of the straight line frequency typehaving movable andstationary plates centered with respect to one another.

Still further it is aimed to provide a novel form of cut out rotor and stator plates wherein sections of the plates cooperate with one another during partial rotation of the dial controlling the movable plates, while other portions of said plates cooperate with one another simultaneously with the first named sections of the plates upon further rotation of the dial.

Still further it is aimed to provide for the distribution of thestations in a radio reception device so that the present wave lengths, from 400 to 600 meters, will be positioned at the upper end of the dial and room will be provided for a series of stations of low wave lengths, say 50 to 150, at the lower end of the dial.

These and other advantages, capabilities and features of the invention will appear from the subjoined detailed description of one specific embodiment of the invention as illustrated in the accompanying drawings in Fig. 1 is a side elevation condenser element.

Fig. 2 is a front view of the condenser element including the plates.

in section of the Fig. 3 is a front elevation of one form of rotor and stator plates.

Fig. 4 is a front elevation of a modified form of condenser plates.

Fig. 5 is a front elevation of a still further modification.

Fig. 6is a graphical representation of the frequency plate displacement characteristics of the condenser.

Fig. 7 is a graphical representation of the capacitance plate displacement of the condenser, and

Fig. 8 is a diagrammatic representation of the changed reception diagram caused by the use of the new condenser.

Referring more particularly to the reference characters in the drawing; numeral 1 represents the panel on which the condenser is adapted to be fastened by means of posts 2 positioned along the outer portion of the end plate 3, which end plate cooperates with a second end plate 4 for containing therein the movable and fixed elements of the condenser.

Referring particularly to Figs. 1 and 2; the condenser element consists of the shaft element 5 passing through the panel 1 and having the dial member 6, at its outer extremity, which shaft element is supported in bearings 7 and 8 formed on the end plate members 3 and at. A series of movable plates 9 are fixed on the shaft 5 and held firmly thereon by means of washers 10 herein shown as partly hexagonal and partly cylindrical in shape, the end washers being formed as hegagonal nuts to position the movable plates 9 with respect to the end plates 3 and 4.

A lug 11 is formed on the washer end 10, for contacting with a plurality of stop members 12 for limiting the rotation of the movable plate members 9 only one of which stop members is herein shown, the other being exactly 180 degrees apart. A plurality of fixed stator plates 13 are positioned within the end plate members 3 and 4, which fixed plates are supported at their end extremities on spindles 14 fastened to non-metallic insulating plates 15, which plates are attached on each side of each end plate by means of rivets 16 and a fixed spindle member 17 respectively. As is noted in Figs. 2 to 5, the fixed stator plates have a support at their end extremities only, though the means of support can be varied without departing from the scope of disclosure indicated by the invention. So far the description has been limited to the ordinary form of condenser. In other words, the structural details of the position of the respective condenser plate elements which form the subject matter of the invention has been indicated in their well known positions in the condenser proper.

Referring particularly to Figs. 2 to 5 here- 'in: it should be noted that the configuration of therespective rotor and stator plate elements indicated as 9 and 13 respectively form the essence of this invention. It is noted in Fig. 3 that the rotor element 9 is pivoted about the shaftmember 5, the said rotor element being positioned centrally thereof and being formed of an aluminum blank having a plurality of cut out spaces 18 and 19 respectively so that the shape of one side, that is, the right side of the condenser element with respect to its metallic portion is like a V whereas the left handed portion of the condenser element is of Vshape with a connecting link 20, extending between the center and the extremity of said plate. The stator plate 13 is shown as having a plurality of cut out portions 21 and 22 respectively, of which the portion 21 is symmetrical to the cut out portion 18 but positioned in reciprocal relation thereto so that the two curves 23 and 24, formed by cutting out the rotor and stator plates, are reciprocally symmetrical to one another. As the rotor plate 9 in Fig. 3 is turned in a clockwise direction toward the stator plate 13 the period of the inductive contact between the rotor and stator plates is limited to the extent of co-action of the curve surfaces 23 and 24 with each other. Referring particularly to Fig. 4 it is noted that the rotor plate has a cut out portion 25 at the right hand side thereof to form the V at the right of the center thereof, and similarly the stator plate 13 has a cut out portion 26 symmetrical to and oppositely or reciprocally disposed of said out out portion 25 of the rotor plate so that the curve portion 27 of the rotor plate will form a curve reciprocal to and symmetrical with the curve 28 with which it coacts as the rotor plate is moved to the right by the actuation of the dial member 6.

Referring particularly to Fig. 5: wherein a modification of the invention is shown, it is noted that the rotor plate 9 and the stator plate 13 have cut out sections 29 and 30 which are symmetrical with and positioned in inverse relation with respect to the cut out portions 31 and 32 of the stator plate so that the plate sections 33, 34, and 36 respectively are reciprocally symmetrical to one another. However, a portion of the condenser plateis formed about the shaft member 5 about which the movable plate is pivoted, which portion 37, consisting of a plurality of oppositely extending wings or fins, cooperates with the wings or fins of the U shaped projection 38, extending upwardly from the-base of the stator member. In this manner as the rotor plates 9 are actuated by the dial member 6, the arms of the projection 37 of the rotor first co-act with the arms 38 of the stator plate for a considerable period of rotation of said dial member on the shaft 5 to which it is bringing in stations at the low wave lengths.

As the rotor plate is further actuated in a clockwise direction, the portion 33 of the rotor plate cooperates with a co-acting portion 34; on which portions the curves are reciprocally symmetrical to bring in the stations with higher wave lengths at a straight line frequency action.

The further rotation of the rotor plate 9 will cause the portion 33 to cooperate with 32, and 35 to cooperate with 34, which are rotation is within 10 to 90 percent of the total rotation of the dial 6.

As the dial is rotated from 90 to 100 percent of its total are of movement, the second wing 37 of the rotor plate cooperates with 'the wing 38 of the stator plate, whereas the first wing 37, of the rotor plate cooperates with the second wing 38 of the stator plate. In this manner a straight line capacity function is introduced into the capacity curve of the condenser as shown in Fig. 7. However, at the same time, the frequency characteristics are that of the straight line frequency'curve shown in Fig. 6.

Referring particularly to Fig. 8, it should be noted that by the application of, this particular form of cut out rotor and stator that the applicant has been able to bunch all of the stations with a wave length of 400 to 600,

at the upper end of thedial, whereas, previously they had been bunched at the lower end of the dial as shown in the calibrated dial 40. In the new calibration dial 41 the,lower portion thereof is open for the positioning therein of new stations operating on low wave lengths. i

It is obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of the invention as set forth in the appended claims. 4

What I claim is:

1. In an electric current controlling instrument, in combination with a series of W- shaped stator plates, rotor plates of similar shape co-acting with said stator plates, the inner edge of the arm portions of said rotor plates being adapted to coincide with the inner edges of the arm portions of the stator plates, means for actuating said rotor plates, projections at the central portion of said rotor and stator plates, which project-ions cooperate with one another, prior to the cooperation of the remaining portions of said stator and rotor plates.

. 2. In an electric current controlling instrument, the combination with a series of statorplates having cutout portions, whereby to form a plurality of outwardly extending arms, projections extending outwardly from the center portion of said stator plates,

'and rotor plates symmetrical to and movable with respect to said stator plates, the edges of the arm portions adjacent the cutout portions of said stator and rotor plates being 'the adjacent cutout arm portions of the rotor and stator plates being adapted to coincide upon movement of said rotor plates, said pro Jections 1n the. central portion of said plates being adapted to cooperate prior to the arm portions of said plates.

L A variable condenser having rotor and stator plates cooperating" with one another. said rotor and stator plates having cutoutportions, thereby providing curved edges ot arm portions adjacent the cutout portions. the said curved edges ot. said arm portions being adapted to coincide with one another during: movement and upon complete displacement ot the rotor plates.

5 In an electric current controlling instrument. the combination with a series of stator plates consisting of a plurality of outwardly extending arms. and a plurality of fins extending outwardly of the center portion of said plates, the ar *a between the arms and the fins being cut out, of a plurality of rotor plates having cutout portions synnnetrical to that of the stator plates.

6. In an electric controlling instrument. the combination with a series of rotor plates, having a body portion disposed centrally thereof. and arms extending outwardly from each side thereof. in the form of segments of a circle, a shaft member attachable centrally of said rotor plates for rotating the same, stator plates symmetrical to said rotor plates, said rotor plates being adapted to coincide with said stator plates upon the" actuation thereof. projections extending outwardly from the center portion of said stator and -rotor plates, whereby the projections of the respective rotor and stator plates will coact with one another prior to the co-action of the arms of said plates.

7. In electric controlling instruments. the combination with a plurality of stator plates having each a shank portion, and a plurality of curved arms extending in opposite directions therefrom, projections extending outwardly from the center portion of said shank portion and parallel to said arm portion, rotor plates of formation similar to said stator plates, and having each apertures disposed centrally of said shank )ortion, ashatt member passing through said apertures for rotating said rotor plates, whereby the curved arms of said rotor plates coincide with the curved armsof said stator plates at the extremity of movement thereof, whereby upon rotation of the shaft, the projections of the. stator plates coincide with the projections of the rotor plates, prior to the co-acting, ot the arms of the rotor and stator plates.

CHARLES HORTON. 

